Ying Wu and Ming Qu, both 23-year-old electrical engineering graduate students from China, are believed to have been talking inside a car after a late-night study session when they were approached by the killer. Both were found fatally shot:

Shortly before the attack, Qu double-parked his BMW outside the home where Wu rented a room. She came outside, sources said, and the two were believed to be sitting in the car talking when the killer either walked or drove up to the car about 1 a.m. Wednesday.

Police are examining robbery as a possible motive in the case, but emphasized that it is very early in the investigation.

Wu was shot once in the chest. Qu was shot multiple times, including a gunshot wound to the head, police said. At some point, Qu got out of the car and attempted to get help. He collapsed on a nearby porch before being able to get help.